The invention relates to a method of manufacturing an anti-static, light-absorbing coating on a display window.
The invention further relates to a method of manufacturing an anti-static, light-absorbing coating consisting of more than one layer on a display window.
The invention also relates to a display device comprising a display window provided with an anti-static, light-absorbing coating.
Anti-static coatings are applied to the display window of a display device, for example to cathode ray tubes, or to the display window of a plasma display panel (PDP). These layers are sufficiently electroconductive to ensure that a high electrostatic voltage present on the outer surface of the display window is removed within maximally a few seconds. By virtue thereof, it is precluded that a user experiences an unpleasant shock if he touches a display window. In addition, the attraction of atmospheric dust is reduced.
An anti-static layer comprises an electroconductive material, which customarily includes antimony-doped tin oxide (ATO). Known coatings comprise, in addition to said anti-static layer, one or more layers having, for example, an anti-reflective or anti-glare effect, or a layer which improves the scratch resistance or selectively influences the light transmission. These further layers are customarily provided by spinning or spraying a silica layer.
A method of the type mentioned in the opening paragraph is known from "Japan Display 1992--pp. 289-292: "Anti-Glare, Anti-Reflection and Anti-Static (AGRAS) Coating for CRTs"" by H. Tohda et al. In said document, a description is given of a method in which a display window is provided with a conductive (anti-static) SnO layer by means of CVD (Chemical Vapor Deposition), whereafter a central and outer SiO.sub.2 layer is provided by spinning and spraying, respectively, and a thermal treatment.
This method is laborious and time-consuming; the CVD process takes place in a separate reaction chamber. After the application of the SnO layer, the surface is subjected to polishing and cleaning treatments.